Java判断文件是否为Zip压缩文件

package com.cntrust.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

public class ZipUtils {

	private static byte[] ZIP_HEADER_1 = new byte[] { 80, 75, 3, 4 };
	private static byte[] ZIP_HEADER_2 = new byte[] { 80, 75, 5, 6 };

	/**
	 * 判断文件是否为一个压缩文件
	 * 
	 * @param file
	 * @return
	 */
	public static boolean isArchiveFile(File file) {

		if(file == null){
			return false;
		}
		
		if (file.isDirectory()) {
			return false;
		}

		boolean isArchive = false;
		InputStream input = null;
		try {
			input = new FileInputStream(file);
			byte[] buffer = new byte[4];
			int length = input.read(buffer, 0, 4);
			if (length == 4) {
				isArchive = (Arrays.equals(ZIP_HEADER_1, buffer)) || (Arrays.equals(ZIP_HEADER_2, buffer));
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (input != null) {
				try {
					input.close();
				} catch (IOException e) {
				}
			}
		}

		return isArchive;
	}
	
	public static void main(String[] args) {
		File file = new File("C:/Users/Administrator/Desktop/ttt.rar");
		System.out.println(isArchiveFile(file));
	}

}